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Selective chemical modification of Cys 264 with diiodofluorescein iodacetamide as a tool to study the membrane topology of cytochrome P450scc (CYP11A1)
Author(s) -
Chernogolov Alexey,
Usanov Sergey,
Kraft Regine,
Schwarz Dieter
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)80177-0
Subject(s) - adrenodoxin , cholesterol side chain cleavage enzyme , hemeprotein , chemistry , stereochemistry , cytochrome c , cytochrome p450 , cytochrome , cleavage (geology) , topology (electrical circuits) , biophysics , biochemistry , enzyme , biology , heme , mitochondrion , fracture (geology) , mathematics , combinatorics , paleontology
Cys 264 of cytochrome P450scc (CYPIIAI) was selectively labelled with diiodofluorescein iodacetamide in solution and in proteoliposomes. The labelling affected the interaction of P450scc with adrenodoxin and significantly inhibited the side‐chain cleavage activity of the soluble and membrane‐bound hemeprotein in the reconstituted system. In proteoliposomes both the labelled and unlabelled hemepoteins were susceptible to trypsin and split into F1 and F2, two fragments corresponding to the two main domains of P450scc. These results suggest that the hinge connecting the two domains in the region Arg 250 ‐Asn 257 is exposed to the surface of the membrane and involved in the interaction of P450scc with adrenodoxin.